In-situ Cu2O/Cu interfaces generation on Cu2O nanocubes toward enhanced C2+ selectivity

Abstract

The electro-reduction of CO2 to C2+ products has received a lot of attention because it provides a pathway to obtain feedstocks and fuels by renewable electricity. It is well known that Cu-based catalysts are selective for C2+ products, although the catalytic mechanism of its surface structure is not fully understood. Therefore, we procured Cu2O nanocubes via a wet chemical reduction approach, and then Cu2O/Cu catalyst was in-situ generated during the electro-catalytic CO2 reduction reaction (CO2RR). The electrochemical properties of Cu2O/Cu catalyst are better than those of Cu catalyst. In particular, the selectivity of Cu2O/Cu catalyst for C2+ products is 55.9 %, which is approximately 67 % higher than that of Cu catalyst at the optimal catalytic voltage of –1.1 V versus reversible hydrogen electrode (RHE). In addition, the stability of Cu2O/Cu catalyst is up to 30 h, and the catalytic current density is significantly higher than that of Cu catalyst. Using in-situ Raman spectroscopy, the signal peaks of transition state intermediates (*CO–Cu and CO) of Cu2O/Cu catalyst are stronger than those of Cu catalyst during CO2RR. Density function theory (DFT) calculations suggest that the good electrochemical performance is associated with the Cu2O/Cu interfaces, which significantly improves the thermodynamics and kinetics of CO2 activation and CO dimerization. This study provides a simple approach for improving catalytic performance and will advance the understanding of the role of the Cu2O/Cu interfaces in CO2RR.